The first, which we brought to you last September courtesy of the University of Rochester, says video games enhance reaction time and improve the likelihood that a gamer will make the right decision under pressure.
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But on the other side of the issue we have a new study released today by Continental Tire in the print edition of Metro. Contrary to the Rochester results, Continental finds that frequent players of titles like Gran Turismo and Grand Theft Auto are more likely to crash their real-life cars than those that don't.

Personally, I'd lean towards "which kind of game do you play?", since there are simulators for driving/racing and simulators that almost qualify as a demolition derby. As for the rest, well... self-reporting studies trying to correlate with other data are notoriously unreliable.